Animal Performance with and without Supplements in Mombaça Guinea Grass Pastures during Dry Season.

The objectives were to: 1) evaluate the potential of the animal performance on Panicum maximum cv. Mombaça (mombaça guinea grass) pasture during dry season, and 2) determine the effects of protein or protein-energy supplementation on liveweight gain of steers grazing guinea grass pasture. A complete randomized block design was employed with three treatments and three replicates. Treatments included non-supplemented animals (NS) and animals supplemented with protein (PS) or protein-energy (PES), provided at 0.15% or 0.6% of body weight for 115 days, during dry period. We used 36 weaned calves from initial bodyweigh (LW) of 192 kg (±5 kg) on nine plots of mombaça guinea grass (1.25 ha each). Each month, animals were weighed and pastures sampled to estimate forage characteristics. The average daily gain (ADG) was greater (P = 0.0001) for cattle fed supplement than for cattle fed no supplement (250 g steer-1), and greater for protein-energy supplement (770 g steer-1) than for protein supplement (460 g steer-1). Mombaça guinea grass pastures with 45 cm height at the end of the wetseason have enough forage mass for maintenance throughout the dry season about 1.4 AU ha-1 (AU = 450 kg BW), and reasonable nutritive value (average of 8,1% of crude protein and 55,3% of in vitro organic matter digestibility) to provide small gains. Considering the nutritive value of Mombaça guinea grass during the dry period, protein and energy supplementation is required for weaned calves to optimize their performance

Efectos de diferentes suplementos en el rendimiento de novillos que pastorean guinea Mombasa (Megathyrsus maximus) durante el período seco.

ABSTRACT - To mitigate the low animal performance on Mombaça guineagrass pasture during the dry period, feeding 2 types of supplement to 2 genetic groups was evaluated. The experimental design was a randomized block design following a 2 × 2 factorial arrangement with 4 replications. The treatments consisted of feeding 2 levels of supplement (0.25 and 1.0% of body weight; BW), named low-cost supplement (LCS; US$11.75/steer) and high-cost supplement (HCS; US$ 62.80/steer), respectively, for 130 days (July–October; dry season) to 2 genetic groups: Caracu and F1 Senepol × Caracu. The steers were supplemented daily and weighed every 28 days. Pastures were evaluated monthly to estimate the herbage accumulation rate, herbage mass (HM), leaf, stem and dead material percentages and nutritive value. HM, morphological components and nutritive value were independent of supplement type fed (P>0.05). There were decreases in HM (3,720 to 3,205 kg DM/ha), daily herbage allowance (14.0 to 9.4 kg DM/100 kg BW) and leaf percentage (33.4 to 21.2%) and increase in dead material percentage (53.3 to 67.7%) throughout the experimental period. In vitro organic matter digestibility (59.9%), crude protein concentration (10.0%), neutral detergent fiber (72.1%) and acid detergent lignin (2.9%) remained constant from July to September but increased markedly in October. Steers supplemented with HCS performed better (P<0.05) than those which received LCS (1.005 vs. 0.565 kg liveweight gain/head/day, respectively). Regardless of supplement type, F1 Senepol × Caracu steers had greater average daily gains than pure Caracu steers (0.88 vs. 0.71 kg/hd/d, respectively). Feeding HCS to steers in the dry season would produce better performance than LCS and could reduce time to reach slaughter weight but weight changes during the subsequent wet season should be monitored to assess the extent of any compensatory gain by the low-cost group during this period to reduce the weight advantage of the high-cost group

Nitrogen fertilisation in tropical pastures: what are the impacts of this practice?

It is estimated that approximately 47% of the world?s ruminant meat and milk is produced in tropical and subtropical regions, with pasture comprising the main food base of these animals. Nitrogen fertilisation is an essential practice for the maintenance of pasture productivity, considering that a deficiency of this nutrient is a primary factor in triggering pasture degradation. In addition to directly influencing the photochemical and biochemical phases of photosynthesis, nitrogen stimulates enzyme activity and the synthesis of enzymes responsible for fixing CO2 (Rubisco in C3 plants and phosphoenolpyruvate carboxylase in C4 plants), thus increasing the efficiency of atmospheric CO2 capture. All of these physiological processes are easily observed macroscopically in the characteristics of forage plants. This review examines the impact of nitrogen fertilisation in tropical pastures on the main components of production systems (soil, plants and animals), describes the results obtained in different situations and highlights the most efficient ways of producing meat without environmental impacts

Short-term protein-energy supplementation at weaning or in the transition of dry-rainy season on performance of Nellore calves kept on Mombaça or Marandu grasses.

ABSTRACT - The objective was to examine the effect of two short-term proteinenergy supplementation (STPES) strategies at the rearing phase on the performance of Nellore calves grazing on Mombaça or Marandu grasses. The experiment used 72 calves (7-mo old, 229±3.0 kg body weight [BW]) allotted in a completely randomized block design to four treatments in a 2 × 2 factorial arrangement: two forage cultivars (Panicum maximum cv. Mombaça vs. Brachiaria brizantha cv. Marandu) and two STPES (WEAN – STPES immediately after weaning vs. TRAN – STPES in the transition of dryrainy). The WEAN animals received 1 kg day−1 (n = 36) of a protein-energy supplement, whereas TRAN animals were subjected to STPES at 2 g/kg BW day−1 (n = 36), both for 53 days. Every 28 days, calves were weighed to measure performance, and pastures were sampled to evaluate productive and structural traits. Growth performance was analyzed considering a completely randomized block design with a 2 × 2 arrangement of treatment, whereas forage responses included repeated measures. Marandu had a higher forage mass (3,586 kg) than Mombaça (2,890 kg), but there was no difference in forage mass in each cultivar between preconditioning periods. The nutritional composition of Marandu and Mombaça cultivars did not differ and had similar results of in vitro fermentation variables. Stocking rate was higher for WEAN, in the Mombaça pastures. The STPES at weaning on Marandu provided greater gains per area. When applied in the period following the weaning and coinciding with the dry season, the STPES improves the performance of newly weaned calves kept on Marandu and Mombaça grasses

Massa de raízes de forrageiras submetidas a doses de fósforo e nitrogênio em Neossolo Quartzarênico Órtigo da Região de Campo Grande - MS.

O gênero Brachiaria tem fornecido importantes espécies forrageiras para as regiões tropicais. No mercado há várias espécies e cultivares do gênero, com o intuito de atenter diferentes sistemas de produção, com níveis tecnológicos distintos. No entanto, a proposição de estratégias de manejo da fertilidade do solo para garantir o fornecimento de nutrientes em quantidades e proporções equilibradas, aliada ao manejo do pastejo, promovendo melhorias no processo produtivo das pastagens, é uma necessidade premente (Costa et al., 2010). Os estudos com sistema radicular de plantas forrageiras são importantes para a compreensão das inter-relações entre os solos, plantas e outros organismos vivos (Cecato et al., 2004). As raízes constituem um sistema bastante complexo, responsável pelo suprimento de água e de nutrientes (Teruel et al., 2000).Título em inglês: Roots mass for forage submitted to Phosphorus ad nitrogen doses in typic Quartzipsamments Soil on Campo Grande - MS Region